During the manufacture of a thin film transistor liquid crystal display (TFT-LCD), it is required to apply a uniform alignment film made of an aligning agent onto a glass substrate of a liquid crystal cell, so as to align liquid crystal molecules thereon in a certain direction and deflect the liquid crystal molecules in a prescribed direction under the control of an electric field, thereby to achieve normal display of the liquid crystal display panel including the liquid crystal cell.
FIG. 1 shows a procedure of forming the alignment film on the glass substrate. At first, an aligning agent 101 is dripped by a dispenser 102 onto a place where an anilox roller 103 is in contact with a scraper 104, and coated uniformly onto the anilox roller 103 by the scraper 104. Then, the anilox roller 103 is in contact with a printing roller 106 having a transfer plate 105 with a predetermined pattern, so as to transfer the aligning agent 101 onto the transfer plate 105. Finally, the aligning agent 101 is printed by the transfer plate 105 onto a surface of a glass substrate 108 on a table 107 to form the alignment film. As shown in FIG. 2, the transfer plate 105 includes a base film 109 and a plurality of dots 110 arranged on the base film 109 at an identical density and an identical size. The amount of the aligning agent 101 adsorbed between the dots 110 is the same.
During the actual production, due to limitations of a transferring technique adopted by the transfer plate, the aligning agent 101 will flow in a printing direction and be spread from the center to the edge when it is printed onto the glass substrate 108. When the aligning agent 101 at the edge of the transfer plate is in an oversaturation state and printed onto a periphery of a display region of the glass substrate 108, a halo region will occur due to a resultant over-thick edge of the alignment film, and thereby the alignment film will be of a non-uniform thickness.
As shown in FIG. 3, a convex part of the alignment film 111 on the glass substrate 108 is just a halo region 112. FIG. 4 is a top view of a liquid crystal display panel including the halo region 112, where 113 represents a display region. When there is the halo region 112 at the display region of the liquid crystal display panel, non-uniform rubbing alignment will occur, and thereby the liquid crystal molecules will be aligned abnormally.